<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>

  <style>
    .right{
    position: relative;
    width: 200px;
    height: 250px;
    overflow: hidden;
}
								.rightcircle{
    width: 200px;
    height: 200px;
    border:8px solid transparent;
    border-radius: 50%;
    position: absolute;
    top:0;
    right: 0;
    border-top:8px solid #38B99B;
    border-right:8px solid #38B99B;
    -webkit-transform : rotate(45deg);
    -moz-transform : rotate(45deg);
    -o-transform : rotate(45deg);
    transform : rotate(45deg); /* 旋转45度 */
}
	
  </style>
</head>
<body>
  <div class="right">
    <div class="rightcircle"></div>
  </div>
</body>
</html>